Cookie Policy
Chattr — Cookie Policy
1. About this policy
This Cookie Policy explains how CHATTR LTD ("we", "us", "our"), a company registered in England and Wales (company number 17199526), uses cookies and similar technologies on Chattr. It should be read alongside our Privacy Policy.
2. What cookies are
Cookies are small text files placed on your device when you visit a website. Similar technologies include "local storage" and "session storage", which also store small amounts of information in your browser. We use the word "cookies" in this policy to cover all of these. They are widely used to make websites work, to keep you signed in, and to keep services secure.
3. Our approach
We use strictly necessary cookies to run the Service. We use a few first-party cookies and storage items for our own signup statistics, product analytics and the invite scheme; these are never shared with advertisers, and you can turn signup statistics and analytics off at any time in Settings → Privacy choices. We also use advertising cookies that help us see which of our adverts bring students to Chattr — but only if you consent. We ask before any advertising cookie is set, and the Service works exactly the same whether you accept or refuse. You can change your mind at any time in Settings → Advertising cookies.
4. The cookies we use
This is everything Chattr stores on a student's device (staff accounts also keep one setting for the admin campus picker):
| Name | Type | What it does | How long |
|---|---|---|---|
| sb-… (several, set by Supabase) | Strictly necessary cookie | Keeps you signed in and protects your account | While you stay signed in |
| chattr_ad_consent | Strictly necessary cookie | Remembers whether you accepted or refused advertising cookies | 6 months |
| chattr_stats_off | Strictly necessary cookie | Remembers that you turned signup statistics off | 1 year |
| chattr_ref | Cookie (invite scheme) | Remembers whose invite link you opened, so the invite can count | 30 days |
| chattr_signup_source, chattr_attribution | Cookie (signup statistics) | Remembers which link, advert or campaign brought you to Chattr; first-party, never sent to Meta | 30 days |
| chattr_utm | Local storage (signup statistics) | A copy of the same campaign tags, for in-app browsers that drop cookies | 30 days |
| chattr_opened | Session storage (analytics) | Tells a fresh visit from a reload for our product analytics | Until you close the tab |
| chattr_ev_sid | Session storage (analytics) | A random number for this visit, so our own usage record can tell one visit from another | Until you close the tab |
| chattr_ab | Cookie (analytics) | Before you sign in, a random number that keeps you on the same version of a page we are testing; set only while a test is running and only if you have not turned analytics or signup statistics off; never sent to anyone else | 90 days |
| chattr_exp_seen:… | Session storage (analytics) | Remembers that this visit has already been counted in a test, so it is counted once | Until you close the tab |
| chattr_theme, chattr_university_id, chattr_university_name, chattr_universities_cache_v3 | Local storage (preferences) | Your light or dark theme and your campus name for display | Until you clear them |
| chattr_install_prompt_dismissed, chattr_install_prompt_dismissal_time, chattr_intro_seen, chattr_activation_card_hidden, chattr_onboarding_pending, chattr_recent_searches, chattr_legal_seen | Local or session storage (preferences) | Remembers prompts and cards you dismissed, whether you have seen the intro and the latest policy-update notice, and your recent searches on this device | Until you clear them (session items until you close the tab) |
| chattr_analytics_off | Local storage and cookie (strictly necessary) | Remembers that you turned analytics and session replay off on this device, so neither the app nor our servers record usage from it | Until you clear it (the cookie lasts 1 year) |
| _fbp, _fbc (set by Meta) | Advertising cookie — only if you accept | Lets us measure whether people who saw a Chattr advert went on to sign up | Set by Meta (typically up to 90 days) |
Our hosting provider (Vercel) and sign-in provider (Supabase) may set short-lived technical cookies on our behalf to keep the Service running and to protect against abuse; these are strictly necessary. The Privacy Policy lists these providers.
Product analytics. Our product analytics tool, PostHog, runs without cookies at all: it keeps what it needs in memory and forgets it when you leave the page. The only thing stored for analytics is the chattr_opened marker above. You can turn analytics and session replay off on a device in Settings → Privacy choices.
Advertising — only with your consent. If you accept, Meta Platforms Ireland Limited sets cookies (_fbp, and _fbc if you arrived from one of our adverts) that let us measure how many people who saw a Chattr advert went on to create an account. We also send Meta a record of those same signup steps directly from our servers, with your email address and phone number turned into an irreversible code (a SHA-256 hash) so Meta can match it against their own records without us handing over the address itself. That code is still information about you, so we treat it as your personal data. For this measurement we never send Meta anything you post, comment on or read on Chattr, and we send nothing at all unless you have accepted. (Chattr's own adverts may carry the words of a post, with no name or identifying detail: see section 4 of the Privacy Policy.) Meta and Chattr are joint controllers for this measurement — you can exercise your rights with either of us, and Meta may transfer this data outside the UK under the UK extension to the EU-US Data Privacy Framework and standard contractual clauses.
5. What we do not use
- Third-party tracking, profiling or cross-site cookies beyond the advertising measurement described in section 4;
- Analytics cookies that identify you individually — our product analytics (PostHog) runs without cookies at all;
- Any cookie that records the content you write or read on Chattr.
6. Managing cookies
Advertising cookies: turn them on or off at any time in Settings → Advertising cookies. Signup statistics and analytics: turn them off in Settings → Privacy choices. Refusing, or later withdrawing, costs you nothing — every part of Chattr works the same either way. Strictly necessary cookies cannot be turned off, because blocking them stops parts of the Service working — for example, you may not stay signed in. You can also control cookies through your browser settings, though clearing them will sign you out of Chattr.
7. Changes to this policy
We may update this Cookie Policy from time to time. The "last updated" date shows when it last changed. If we begin using other non-essential cookies, we will update this policy and seek consent where required.
8. Contact
Questions: privacy@chattr.uk. You can also complain to the Information Commission (formerly the ICO) at ico.org.uk or on 0303 123 1113.
Last updated: 4 October 2026
CHATTR LTD, registered in England and Wales, company number 17199526. Registered office: 71-75 Shelton Street, Covent Garden, London WC2H 9JQ. support@chattr.uk